Posted on August 18, 2020 3:32 am
 |  Asked by Rajesh Mishra
Answered on August 18, 2020 3:51 am

Hi Rajesh,

Thank you for contacting Arista.

Port mirroring, also known as port monitoring, is the duplication of traffic from a collection of source ports to a destination port.Port Mirroring is achieved by configuring one or more mirroring sessions. A mirroring session is an association between a set of mirror source ports (ports whose traffic is being mirrored as part of the session) and a mirror destination port (a port to which mirrored traffic is sent). Port mirroring is performed in hardware on all platforms.

You can refer to the below document for more information regarding port mirroring, configurations:


Let us know if you are facing any issues with respect to capturing mirrored traffic.You can also open a case with Arista TAC by dropping a mail to




Posted by Alexis Dacquay
Answered on August 18, 2020 11:02 am

Port mirroring is using the syntax:
monitor session

A great use case of Mirroring monitor session is for sending packet capture directly to the switch itself, via the:
destination cpu.

It allows you watching on the switch itself what dataplane traffic is forwarded.
tcpdump monitor

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